1. Field of the Invention
This invention generally relates to picture projection and display systems and, more specifically, to motion picture film displays and apparatuses which provide a continuous picture on a substantially circular screen.
2. Description of the Related Art
Motion picture systems which display the picture on a 360.degree. cylindrical screen are becoming increasingly popular in theme parks, amusement centers and local and international exhibits. The illusion of being completely surrouded by the film environment is visually overwhelming and psychologically satisfying.
A typical panaramic motion picture presentation arrangement is shown in U.S. Pat. No. 2,942,516, issued to Disney et al. It includes a plurality of conventional rectangular screens oriented in a large circle. Each screen is separated from its neighbor by a vertical strip of non-reflecting material. A small projection port is provided at the approximate center of each of the separating strips, behind which lies a projector. Persons viewing the picture stand beneath this circular viewing screen arrangement.
One serious problem with this type of system is degradation in picture contrast and color saturation caused by projected light being reflected off of one screen and onto the screen opposite it. This is known as "cross-talk" or "re-illumination."
Another problem with systems of this type is that the perceived brightness of each picture is lessened because the reflected light off of each screen is not principally focused toward where the majority of viewers is present, i.e., the center of the system. Picture linearity is also poor since rectilinear film images are projected onto surfaces which, from the projector's perspective, appear to be curved. This results in what is commonly referred to as "horizontal sag" below the center of each screen and "scalloping" above the center. Vertical images, such as buildings, also tend to converge upward creating the illusion of "falling away" from the viewer.
Systems of this type are also restricted to an odd number of screens because of the need to project from the approximate center point of the opposing intersection of two screens. This is not always desirable. For example, a taller picture can be obtained without changing the aspect ratio by switching from a nine-to an eight-screen system without significantly sacrificing the circular picture effect. This obviously cannot be done in systems of the type shown in the Disney U.S. Pat No. 2,942,516, which are limited to an odd number of screens.